Year	Years
1800	31.8
1801	31.8
1802	31.8
1803	31.8
1804	31.8
1805	31.8
1806	31.8
1807	31.8
1808	31.8
1809	31.8
1810	31.8
1811	31.8
1812	31.8
1813	31.8
1814	31.8
1815	31.8
1816	31.8
1817	31.8
1818	31.8
1819	31.8
1820	31.8
1821	31.8
1822	31.8
1823	31.8
1824	31.8
1825	31.8
1826	31.8
1827	31.8
1828	31.8
1829	31.8
1830	31.8
1831	31.8
1832	31.8
1833	31.8
1834	31.8
1835	31.8
1836	31.8
1837	31.8
1838	31.8
1839	31.8
1840	31.8
1841	31.8
1842	31.8
1843	31.8
1844	31.8
1845	31.8
1846	31.8
1847	31.8
1848	31.8
1849	31.8
1850	31.8
1851	31.8
1852	31.8
1853	31.8
1854	31.8
1855	31.8
1856	31.8
1857	31.8
1858	31.8
1859	31.8
1860	31.8
1861	31.8
1862	31.8
1863	31.8
1864	31.8
1865	31.8
1866	31.8
1867	31.8
1868	31.8
1869	31.8
1870	31.8
1871	31.8
1872	31.79
1873	31.79
1874	31.78
1875	31.78
1876	31.77
1877	31.77
1878	31.76
1879	31.76
1880	31.75
1881	31.75
1882	31.74
1883	31.74
1884	31.73
1885	31.73
1886	31.72
1887	31.72
1888	31.71
1889	31.71
1890	31.7
1891	31.7
1892	31.69
1893	31.69
1894	31.68
1895	31.68
1896	31.67
1897	31.67
1898	31.66
1899	31.66
1900	31.65
1901	31.65
1902	31.64
1903	31.64
1904	31.64
1905	31.63
1906	31.63
1907	31.62
1908	31.62
1909	31.61
1910	31.61
1911	31.6
1912	31.6
1913	31.59
1914	31.59
1915	31.58
1916	31.58
1917	31.57
1918	20.23
1919	31.56
1920	31.56
1921	31.55
1922	31.55
1923	31.54
1924	31.54
1925	31.53
1926	31.53
1927	31.52
1928	31.52
1929	31.51
1930	31.51
1931	31.5
1932	31.5
1933	31.49
1934	31.49
1935	31.48
1936	31.48
1937	31.48
1938	31.47
1939	31.47
1940	31.46
1941	31.46
1942	31.45
1943	31.45
1944	31.44
1945	31.44
1946	33.55
1947	35.67
1948	37.78
1949	39.89
1950	42
1951	42.11
1952	42.38
1953	42.75
1954	43.21
1955	43.78
1956	44.42
1957	45.16
1958	45.98
1959	46.84
1960	47.73
1961	48.62
1962	49.49
1963	50.29
1964	51.03
1965	51.7
1966	52.32
1967	52.91
1968	53.48
1969	54.01
1970	54.52
1971	55.26
1972	55.98
1973	56.72
1974	57.41
1975	58.02
1976	58.19
1977	58.38
1978	58.57
1979	58.76
1980	58.98
1981	59.22
1982	59.55
1983	59.94
1984	60.41
1985	60.87
1986	61.45
1987	61.98
1988	62.16
1989	62.34
1990	62.52
1991	62.56
1992	62.45
1993	62.24
1994	62.08
1995	61.73
1996	61.55
1997	61.71
1998	61.99
1999	62.41
2000	62.82
2001	63.15
2002	63.38
2003	63.53
2004	63.71
2005	63.99
2006	64.5
2007	65.11
2008	65.64
2009	65.94
2010	66.18
2011	66.59
2012	67.05
2013	67.56
2014	68.04
2015	68.21
2016	68.34
2017	68.52
2018	68.69